Sheets of apertured films, woven fabrics and nonwoven materials are widely used in many types of products such as, for example, personal care products, garments, medical fabrics and the like. Some sheets made from certain inexpensive raw materials could have an even wider range of applications in these products if the sheets could be designed to have enhanced properties or attributes.
For example, polyolefins are widely used in the manufacture of sheets of apertured films, woven fabrics, and nonwoven materials. Many types of polyolefin sheets tend to be hydrophobic and relatively inert. That is, the low surface free energy of polyolefins (e.g., polypropylene) and their relatively chemically inert nature render many unmodified polyolefins ill-suited for providing attributes other than those based on hydrophobic interactions.
In the past, chemical coatings and/or internal additives have been added to sheets of materials to impart desired properties. Many of these coatings and/or additives present problems related to cost, effectiveness, durability and/or the environment. These coatings generally provide a uniform wettability or hydrophilicity across one or more dimensions of the sheets of materials. Sheet materials having substantially uniform wettability across their thickness or Z-direction may retain or hold significant amounts of liquid in the cover material instead of releasing the liquid to an absorbent core. This may be particularly noticeable if the liquid is colored or viscous in nature such as, for example, blood or menses. Thus, there is still a need for a permeable material having controlled, non-uniform wettability so that it can be used to direct the transfer or flow of liquid through the material. There is also a need for a permeable, bodyside cover material for use in an absorbent personal care product. There is also a need for a permeable, bodyside cover material for use in an absorbent personal care product which provides non-uniform wettability along at least one dimension of the cover material. This need extends to a permeable, bodyside cover material (for an absorbent personal care product) coated with a readily available, inexpensive, natural, renewable and non-toxic material that can provide non-uniform wettability to a relatively hydrophobic substrate. Meeting these needs is important since it is both economically and environmentally desirable to substitute relatively complex chemical surface modification of inexpensive (and often recyclable) substrates with inexpensive, readily available natural materials.